Estrogen and progesterone are the primary sex hormones in women. Hormones are chemicals that are derived from cholesterol and made by glands in the body. Hormones circulate in the bloodstream and regulate body functions. Estrogen and progesterone are very important to women in not only regulating the reproductive cycle but in protecting their health.
The following illustration shows the female reproductive system.

The Fallopian Tube connects the ovary to the uterus. The ovaries are two small glands that produce estrogen and progesterone, start the menstrual cycle and release an egg once a month until menopause. The uterus is the area where a baby grows. The cervix is the narrow entryway between the vagina and uterus. The vagina is a hollow canal or tube made of muscle that can expand so a baby can pass from the uterus during childbirth.
Prior to menopause, the production of estrogen and progesterone are closely related to a woman’s monthly reproductive cycles.

During this monthly cycle, the amount of circulating estrogen and progesterone in the body is monitored by the hypothalamus, a tiny structure in the brain that has the central role of controlling hormones and the autonomic nervous system.  If more progesterone is needed, the hypothalamus sends a hormone, hypothalamic gonadotropin releasing hormone (gonad refers to the ovaries in women and testicles in men) releasing hormone (GnRH), to the pituitary gland, another important structure in the brain, instructing it to in turn release luteinizing hormone (LH) which tells the ovaries to make more progesterone.

If more estrogen is needed, the hypothalamus sends the same hormonehypothalamic gonadotropin releasing hormone (GnRH) gonadotropin, to the pituitary glandbut this time instructing it to in turn release follicle-stimulating hormone (FSH), which tells the ovaries to produce more estrogen.

Estrogen and progesterone primarily affect:
• Development of breasts
• Development of the uterus and vagina
• Broadening of the pelvis
• Growth of pubic hair
• The monthly preparation of the body for a possible pregnancy
• The actual pregnancy if it occurs
• Keeping bones strong
Blood clotting

When estrogen levels are high in relation to progesterone, women will often experience many severe symptoms, such as
• Breast tenderness
• Cyclical headaches or migraines
• Irregular bleeding,
• Water retention,
• Weight gain, especially around the abdomen
• Hot flashes
• Night sweats
• Irritability
• Difficulty sleeping
• Palpitations
(Note: a number of these symptoms can also indicate the exact opposite condition, a deficiency of estrogen).

The following symptoms occur when there is too much estrogen in relation to progesterone. This could occur because of low levels of progesterone and normal levels of estrogen, or because of high levels of estrogen and normal levels of progesterone. This is why testing is important.
• Post-Partum Depression (this is thought to be mainly due to the sudden drop in progesterone that occurs after delivery of a baby)
• Weight gain, especially around the abdomen
• PMS symptoms
• Fatigue
• Fibrocystic breasts
• Foggy thinking
• Hair loss
• Headaches /migraines
• Hot flashes and night sweats
• Irregular menstrual periods
• Irritability
• Memory loss
Mood swings
• Panic attacks
• Polycystic ovaries
• Pre-menopausal bone loss
• Decreased metabolism
Thyroid dysfunction
• Uterine fibroids
• Vaginal dryness
• Weight gain
• Water retention

As women enter their 40’s, many of them begin to secrete less estrogen as their ovaries actually get smaller.  Ovulation and menstruation become increasingly irregular and eventually will cease.  When ovulation and menstruation cease, this is called menopause.

The average age for the onset of menopause is 52, but many women experience menopause earlier and some later.  By the time menopause starts, estrogen levels are estimated to be less than 10% of prior levels.

As the amount of estrogen produced in the ovaries decreases during the perimenopause period (the time immediately preceding menopause), the hypothalamus senses that the estrogen and progesterone levels are decreasing and orders the pituitary to release more FSH and LH, seeking to stimulate the ovaries.  However, the ovaries are no longer producing estrogen and progesterone in the same amounts.  The hypothalamus then orders the pituitary to release even more FSH and LH into the blood stream.

It is common for the concentrations of FSH and LH in the blood to be ten or more times their former values.   Having this excessive amount of FSH and LH in the bloodstream can cause a variety of unpleasant physical and emotional symptoms because the body believes it does not have sufficient estrogen and progesterone.

One of the major concerns of women during perimenopause and menopause is osteoporosisOsteoporosis literally means “porous bone”.  It is a condition where bones become more porous and more brittle–they become less dense.  In a woman’s body, the estrogen helps replace any bone that is lost.

Since perimenopause signals a decrease in estrogen, women going through this period can begin to experience bone loss.  This can accelerate during menopause and continue for the rest of a woman’s life.

Because of the many uncomfortable and, in the case of osteoporosis, dangerous conditions that can accompany perimenopause and menopause, many physicians recommend taking estrogen and progesterone.
By taking estrogen and progesterone, the hypothalamus senses that there are adequate levels of the hormones and does not cause the thyroid to create excessive LH and FSH.  This leads to an alleviation of the uncomfortable conditions and also has been demonstrated to reduce bone loss.

A study that followed 8,816 women for ten years was published in the Archives of Internal Medicine 2002;162(20):2278-84.  The study concluded that women taking estrogen continuously were less likely to suffer bone fractures.

Dr. Susan Ott, Professor of Medicine at the University of Washington, concluded that studies showed that the use of estrogen increased the density of bones in women younger than 60.

As with many medical treatments, there are studies supporting the use of hormone replacement therapy (“HRT”) and studies indicating problems with HRT. However, there is evidence that HRT is beneficial to many.

In a study published in the New England Journal of Medicine on June 21, 2007, entitled Estrogen Therapy and Coronary-Artery Calcification, it concluded, “Among women 50 to 59 years old at enrollment, the calcified-plaque burden in the coronary arteries after trial completion was lower in women assigned to estrogen than in those assigned to placebo.”

The April 14, 2004 Journal of the American Medical Association (JAMA) published the results of a study entitled Effects of Conjugated Equine Estrogen in Postmenopausal Women with Hysterectomy: the Women’s Health Initiative randomized controlled trial. There were two studies. 16,000 women used progestin (a synthetic hormone having similar properties to progesterone) and estrogen in one study. The second study was comprised of 10,000 women who had had a hysterectomy.  The second group used only estrogen. The first study was terminated after five years because it was determined that there was an increase of breast cancer. The second, with just estrogen alone, was terminated in seven years because of the perceived increased risk of a stroke.

A bioidentical hormone is created in the lab.  Soybeans are used in creating estrogen and yams are used in creating progesterone. The resulting hormone will have the same molecular structure as the estrogen or progesterone naturally created by the body.

The bioidentical hormones most used in HRT are created in compounding pharmacies using a prescription written by the medical doctor who examined the woman.   This prescription will contain the amounts of progesterone, estrogen and even testosterone needed.

In contrast, the hormones produced by drug companies have molecular structures that differ from the molecular structures of natural hormones, and other differences as well, in order for the drug to receive a patent–essential to a drug company seeking to market a drug.

There are conflicting opinions on the value of bioidentical hormones.  To date, there have not been any long-term scientifically based trials as there have been with some of the drug company hormones.  However, an increasing number of doctors are now using bioidentical hormones.

In an article published in the January, 2009 issue of Postgraduate Medicine entitled “The Bioidentical Hormone Debate: Are Bioidentical Hormones (Estradiol, Estriol, and Progesterone) Safer or More Efficacious than Commonly Used Synthetic Versions in Hormone Replacement Therapy?” by Dr. Kent Holtorf, he said, “Bioidentical hormones are associated with lower risks, including the risk of breast cancer and cardiovascular disease, and are more efficacious than their synthetic and animal derived counterparts. Until evidence is found to the contrary, bioidentical hormones remain the preferred method of HRT.”

Dr. Jeffrey Dach, in his blog at, provided his opinion of why there have been so many attacks against the use of bioidentical hormones. Dr. Dach said,

“More on the Medical Information War: Wyeth and other pharmaceutical companies have lost huge amounts of money to their major competitor, bioidentical hormones. Don’t be deceived by the Pharmaceutical Propaganda maligning Bioidentical Hormones.  The medical information war is at full throttle, and one of the ways the Pharmaceutical Industry controls public opinion is through their paid mouthpiece, the American College of Obstetrics and Gynecology, ACOG, which is partially funded by Wyeth… In conclusion, bioidentical hormones used at appropriate dosages are safe, effective, and beneficial for health.  On the other hand, any chemical alteration of a human hormone creates a monster hormone, which is not bioidentical.  These monster hormones should never have been approved for marketing and sale to the American people.  These monster hormones are unsafe, causing cancer and heart disease, and should be banned immediately.”

The importance of proper levels of progesterone and estrogen has not been adequately understood by many patients and their doctors.  If you are having any of the symptoms referred to in this article, it is highly recommended that you have your progesterone and estrogen levels checked and evaluated.